1. Field of the Invention
This invention relates to closure devices, and in particular, relates to an injection molded tamper resistant bottle cap and neck for blow-molded bottles of the kind which are commonly used to hold and transport liquids, such as milk and juice.
2. Description of the Related Art
Injection molded caps for blow molded bottles have been used for many years. Generally, two types of bottle caps are available, push-on caps and thread-on caps. Push-on caps are installed by aligning the cap with the opening of a bottle and simply applying an axial force to the top of the cap. Thread-on caps generally require that the cap and bottle be aligned and that a rotative force be applied to the cap. In some cases, threaded caps, if carefully designed in conjunction with the bottle to which it is applied, can be made so that the rotative force required to install the cap is minimized or even eliminated. These kinds of injection molded caps are often made with low density polypropylene, a common material used in injection molding.
One of the problems associated with injection molded caps relates to the tamper-evident connection which must be created between the bottle cap and bottle. One method of forming a tamper-evident connection is to use a threaded bottle cap which includes a ratchet ring having internal ratchet teeth in combination with a bottle neck having external ratchet teeth. When the bottle cap is screwed on the bottle neck, the ratchet teeth of the bottle cap ride over the mating ratchet teeth on the bottle neck, thereby enabling the bottle cap to be fully tightened on the bottle neck. However, when a user attempts to unscrew the bottle cap using low-to-medium twisting force, the ratchet teeth of the bottle cap positively engage the mating ratchet teeth of the bottle neck, thereby preventing unthreading and unsealing of the cap. When higher levels of twisting force are applied to the bottle cap in the direction of unscrewing, the ratchet ring breaks away from the bottle cap and the bottle cap may be unscrewed from the bottle neck. In this manner, removal of the ratchet ring from the bottle cap serves as visual evidence that the bottle has been opened.
While the combination of a bottle cap with a tamper evidencing ring and a bottle neck with ratchet teeth provides for an acceptable tamper-evident connection, this combination does have its limitations. Specifically, it may be possible for a person to pull the lower edge of the ratchet ring outward and then upward toward the cover of the bottle cap in order to defeat the locking action of the ratchet teeth of the bottle cap and bottle neck. It would then be possible to unscrew the bottle cap without breaking the ratchet ring away from the bottle cap and to screw the bottle cap back on the bottle neck. If this were to occur, there may be little visual evidence that the cap has been unscrewed and subsequently screwed back on the bottle neck. Therefore, present tamper-evident connections between a bottle cap and bottle neck may not provide optimum tamper resistance in certain circumstances.
For the foregoing reasons, there is a need for an improved tamper resistant bottle cap and bottle neck which further limit the ability of a person to tamper with the contents of a bottle. Specifically, there is a need for a tamper resistant bottle cap and bottle neck which limit the ability of a person to pry a tamper evidencing ring with ratchet teeth away from the mating ratchet teeth on a bottle neck, unscrew the cap from the bottle neck, and subsequently screw the cap back on the bottle neck.
It is therefore a primary object of the present invention to provide an improved tamper resistant bottle cap and bottle neck for use in bottles which hold liquids, such as milk and juice.
It is a further object of the present invention to provide an improved tamper resistant seal between a bottle cap and a bottle neck.
It is another object of the present invention to provide a tamper-evident threaded bottle cap with an improved ratchet ring which limits the ability of a person to pull the lower edge of the ratchet ring outward and then upward toward the cover of the bottle cap in an effort to defeat the locking action of the ratchet teeth of the bottle cap and the ratchet teeth of the bottle neck.
It is yet another object of the present invention to provide a bottle neck with an improved circumferential ring which makes it is very difficult to insert an object under the outer lower corner of a ratchet ring of a bottle cap and pry the ratchet ring of the bottle cap away from the bottle neck in an effort to defeat the locking action of the ratchet teeth of the bottle cap and the ratchet teeth of the bottle neck.
The present invention is directed to a tamper resistant bottle cap and bottle neck that satisfy the need for a bottle closure with an improved tamper resistant seal. A bottle closure having the features of the present invention broadly comprises a bottle cap and a bottle neck.
The bottle cap of the present invention includes a circular cover, a skirt depending from the periphery of the cover, and a tamper evidencing ring. The skirt of the bottle cap includes an interior surface having threads for retaining the cap to a bottle neck and a lower end having a circumferential flange with semi-circular outwardly extending tabs. The tamper evidencing ring of the bottle cap includes a plurality of ratchet teeth which are capable of meshing with a matching set of ratchet teeth on a bottle neck. The tamper evidencing ring is connected to the flange by frangible connections between the outwardly extending tabs of the flange and the ratchet teeth of the tamper evidencing ring. Each of the frangible connections is generally defined by an area of overlap between a lower surface of each tab and an upper surface of each of the ratchet teeth of the tamper evidencing ring.
The use of tabs connected to ratchet teeth as a means for attaching the tamper evidencing ring to the skirt of the cap provides for a bottle cap that limits the ability of a person to pull the lower edge of the ratchet ring outward and upward toward the cover of the cap as the strong connections between the tabs and ratchet teeth resist twisting. Therefore, the design of the bottle cap of the present invention, wherein the attachment of the skirt and the tamper evidencing ring of the bottle cap is made by way of a connection between tabs and the ratchet teeth of the tamper evidencing ring, provides for a bottle cap having increased tamper resistance.
The bottle neck of the present invention includes an opening at its upper end, a cylindrical exterior surface having threads for retaining a bottle cap, a circumferential ratchet portion below the threads, and a circumferential transfer ring below the ratchet portion. The ratchet portion includes ratchet teeth which are capable of meshing with a matching set of ratchet teeth on a bottle cap. The circumferential transfer ring includes an annular top surface and an upwardly extending circumferential ridge on the periphery of the annular top surface.
The threads of the bottle cap and the bottle neck of the present invention are appropriately dimensioned so as to sealingly engage when the bottle cap is screwed onto the bottle neck. After the bottle cap has been screwed onto the bottle neck, a lower edge of the tamper evidencing ring is located adjacent the top surface of the transfer ring and the ratchet teeth of the bottle neck and the ratchet teeth of the bottle cap are engaged so as to prevent unscrewing of the bottle cap relative to the bottle neck without breaking the frangible connections. The location of the lower edge of the tamper evidencing ring adjacent the top surface of the transfer ring provides additional tamper resistance to the combination of the bottle cap and bottle neck of the present invention. Specifically, when the bottle cap is fully threaded onto bottle neck, the ridge of the transfer ring completely surrounds the lower portion of the ratchet ring so that it is very difficult to insert a thin object, such as a fingernail, under the outer lower corner of the ratchet ring. Therefore, it is difficult to insert an object under the ratchet ring and pry the ratchet ring away from the bottle neck in an effort to defeat the locking action of the ratchet teeth of the ratchet ring and the ratchet teeth of the bottle neck.